Baffle for boilers, stills, and the like



June 4, 1929. c. P. MILLS BAFFLE FOR BOILERS, STILLS, AND THE LIKE Filed March 15, 1927 3 Sheets-Sheet l III :4 a 7 M ENTOR.

if A TORNEY J n 4. 1929- c. P. MILLS 1,715,614

BAFF'LE FOR BOILERS, STILLS, AND THE LIKE Filed March 15, 1927 :s Sheets-Sheet 2 1 INVEN T'OR.

mlf I W A TTORNEY June 4, 1929. c 1,715,614 I BAFFLE FOR BOILERS, STILLS, AND THE LIKE File d March 15, 1927 s Sheets-Sheet 5 1 ATTORNEY.

. Patented June 4, 1929.

UNITED STATES PATENT ornca.

cnAnLEs r. MILLS, or PITTSBURGH, PENNSYLVANIA, ASSIGNOR To THE DURALOY OOMPAN'Y, or PITTSBURGH, PENNSYLVANIA, A conronATIoN on DELAWARE.

IBAFFLE FOR BOILERS, STILLS, AND THE LIKE.

Application filed March 15,

In the case of modern boilers, stills and the like, means are employed to prolong the play of thenflames and burning gases from the fuel over the boiler tubes, such means 'comprisin walls called baflies, and WlllCll are assem led ofrefractory units such as terra cotta tile or fire brick. Such refractor} walls are supported either by the tubes themselves or by being arched between the 10 side walls of the furnace.

A These refractory bafiles are characterized by a number of weaknesses which impair their efliciency, cause them to requlre relatively frequent repairs and shorten their lives.

,The. chan es of furnace temperature, due to varying re conditions or the placing the boiler into and taking it out of service, cause alternate expansion and contractlonof the relatively non-elastic refractory units, producing leaks and .holes in the baflies which act toby-pass more or less of the heat currents, thus interfering with or destroying the intended flowso that portions of the tubes are no longer exposed to the full or veffective heating efl'ect. Such expansion and contraction also serve to disintegrate the individualunits- The impingement of the burning gases on the refractory units, which are not of uniform compositlon, also causes such units to disinte rate and drop out of place. Where the refractory bafies are supported on inclined tubes, such baflles be-. come loosened under service conditions and shift or creep from their proper. places.

Where the'fuel used is gas, either natural I or producer, the flames tend to throb, and

due to imperfect mixture sub-explosionsoccur beyond the rimary combustion cham 40 her. Such throbbing and explosions .tend to loosen and break up the baflle.

Again the weight of the refractory walls is consi .erable and consequently the tubes which sup ort the same tend to bend. and

' 5 become lea In the caseof baflles assembled of refractory units and supported by the tubes, the units are laid on the tubes and thus portions of the surfaces of the latter. are masked 1927. Serial No. 175,520.

from the currents of burning gases and the flames, thus causing a loss in effective heatmg area.

The material cost of such baflies is not great compared to the excessive labor cost of installing and the time lost incident to the installing, repairing and replacings.

Unless the baflles are ke t substantially gas-tight, short circuits in t e flow of burning gases are produced which seriously impair the heat application to the tubes and thus materially reduce the,efliciency of the boiler, still or the like.

Again, the refractory units or fragments of the same frequently drop down from the baflles onto the mechanical stokers, causing serious injury to the latter;

The object which I have in View is the provision of bafilles for boilers, stills and the like, which maybe quickly installed, re-

moved and repaired; which will not be subject to the injurious effects of expansion and contraction, nor destroyed or rendered leaky in service; which will at all times maintain the desired travel of the burning gases, and which will not mask the tubes from the burning gases, nor cause the same to become bent nor leaky.

For this purpose I employ baifles comprised of rolled metal plates supported by and in spaced relation to the tubes, and which are too light in'gauge to overload the tubes or to be materially distorted or affected by expansion and contraction.

The plates which form a baflle are as- ;sembled with sealed joints which prevent leakage, and the plates are so anchored in position as to placement.

prevent baflle creeping or di- The joints are also arranged to ermit the individual plates to expand an contract without accumulatin the expansion or contraction over the be e as a whole.

' 'The bafiles may be quickly and easily reaired by the remova and re lacement of individual plates when require The: plates are rolled from suitable steel. For use in the presence of tem eratures not to exceed 900 deg ees Fahr. stee or iron may be employed, but for higher temperatures I use a suitable heat-resistant steelor iron alloy which is unaffected by repeated changes of temperature.

The alloy which I prefer to use isa chrome or chrome-nickel alloy, the percentage of the chrome or chrome and nickel being varied in accordance with the temperatures to which the bafiies are to be exposed.

Again I may employ steel or iron plates which are plated with an alloy such as chrome, as by the electro-plating method.

I providenew and improved means for supportin or anchoring my improved baflies in place w ereby the baflles are held in position against accidental displacement, the plates are permitted to independently expand and contract, and the supporting tubes are not masked from the currents of burning gases.

Other novel features of construction and arrangement of parts will appear from the following description.

In the accompanying drawin s, wherein I have illustrated the best embo iment of the principles of my invention now known tome, Fig. 1 is a side elevation of the tubes, mud drum and headers of a boiler of the Stirling type which is characterized by but showing a boiler of the Ladd type.

wherein the mud drum is connected to a single elevated header by three banks of tubes; Fig. 7 is a similar view of a boiler of the Parker type in which the tubes are horizontally disposed; Fig. 8 is a similar View of a boiler of the Union Iron Works type in which the mud drum is connected by banks of tubes with the three'headers and the headers are also connected by tubes; Fig. 9 is an enlarged detail of one of the baffles shown in Fig. 8; Fig. 10 is a sectional view taken along the line XX in Fig. 9; Fig. 11 is an elevation of a baflle positioned between widely spaced apart banks of tubes; Fig. 12 is an enlarged section taken along the line XII-XII in- Fig. 11; Fi 13 is a detail in plan showing'the over apping ends of two bafile plates with their bolt holes arranged to permit the plates to expand and contract individually, and Fig. 14 is. a sectional view taken along the line XIV-XIV in' Fi 13.

Re erring first to Figs. 1, 2 and 3, 1 represents the banks of tubes which connect the rnu d drum 2 with the headers 3, 4 and 5. 6

represents tubes connecting the headers. 7 represents the bridge wall and 8 the front and rear walls of the boiler furnace.

9, 10, 11, 12, 13, 14 and 15 represent platemetal baflies which are mounted on the tubes in the proper positions to obtain the desired travel of the burning gases relative to the tubes.

In the case of the bafiles 9, 10, 11, 12, 13 and 14, the same are formed by assembling the plates together and mounting them on the tubes in substantially the manner shown in Figs. 2 and 3 wherein 16, 17 and 18 represent three plates which are united in sealed relation and secured to the tubes, one of which is indicated at 19.

The specific disclosure for assembling the plates and for attaching them in place is as follows.

20 represents saddle blocks having one face, the lower'in Figs. 2 and 3, provided with a substantially semi-circular or armate recess 21 which fits around the tube 19. 22 is a U-bolt Whose curved bridge portion completes with the recess 21 the encompassment of the tube 19, the legs of the bolt 22 extending through parallel bolt holesin the block 20 and having nuts 23 screwed up thereon against the surface of the block, thus fixedly, yet detachably, securing the blocks in place on the tubes.

24 represents cleats havin spaced apart holes by means of which sai cleats may be slipped on over the ends of the bolt 22. The ends of the adjacent baflie plates are punched to provide bolt holes and are placed in overlapping relation with the bolt oles in registration and engaged by the legs of-the U-bolts 22. The exterior cleats 25 are then put in place on the bolts and the nuts 26 applied and tightened on the bolts, thus securing the plates in assembled relation. A' row of spaced apart saddle blocks and U-bolts are provided at the proper interval along the overlapping edges of adjacent sheets. 'Thus the same may be positioned on say twelve inch centers.

The bolt holes in the baflie plates are sufliciently large in diameter relative to the U- bolts, or they may be slotted longitudinally of the bafile plates as indicated in Figs. 13 and 14, to permit the plates to expand and contract independently of each other so that there is no accumulation of expansion and contraction in the baflle wall as a whole.

The usual clearance of a sixteenth of an inch in the bolt holes is generally sufiicient, but is referable to elongate the bolt holes in the baffle plates to provide ample clearance.

In Fig. 4 I show the plates bolted to the saddle blocks without the use of cleats. This enables me to bring the baflle closer to only results in a saving of metal but it also 1 lessens the areas in surface contact and thus reduces the frictional resistance as the plates expand and contract. The use of the cleats 24 and also reduces the frictional resistance to the movement of the material of the plates in expansion and contraction.

The ends of the plates'extend to and may abut against or be embedded in the side walls of the furnace.

The plates are rolled in relative narrow width, preferably of about eighteen inches, and this facilitates changes in direction of the bafile formed of said plates. Such changes of direction may be accomplished by bendin one or more of the plates as in the case'o the baffle 14 in Fig. 1. It will be noted that the relative narrow width of the bafile in the direction of the length of the tubes permits the plates to expand and contract independently of each other Without accumulating the total expansion or contraction over the baflle as a whole and without a thrust on the saddle blocks which might cause the same to shift along the tubes. Thus creeping of the baffle relative to the tubes upon which it is supported is avoided. Again the relative narrowness of the plates of which the bafile is assembled minimizes the warping effect of the uneven heating of the large area of the baflie.

Where the temperatures to which the baffies are subjected do not exceed 900 degrees Fahr. rolled steel or iron plates may be employed. Where the temperatures are higher, I employ alloy steel or iron, preferably a chrome or chrome-nickel alloy. Thus for temperatures between 900 and 1400 degrees Fahr. I may employ a low alloy steel or iron containing from 12% to 14% of chrome, or chrome and nickel in the proportion of about 5% of one to 10% or 12% of the other. For use in th'e presence of temperatures of from 1400 to 2300 degrees Fahr. an alloy containing a higher ercentage of chrome or chrome and nickel s ould be used, such as 24% to of the chrome alone, or chrome and nickel in the roportion of 25% of one and 10% of the ot er.

Again I may employ steel or iron plates plated, as by the electro-plating method,

with a suitable heat-resisting alloy, such as chrome.

The cleats are of similar material to the plates. I prefer to use plates rolledto not more by saddle blocks and U-bolts.

than one-eighth inch in thickness. However, under similar heat conditions the plates of steel alloy or iron alloy may be of less thickness than a plate of steel or iron.

The illow blocks are castings which should e of alloy steel or iron where the temperature requires.

In Fig. 5 I haveillustrated in detail the bafile 15 shown in Fig. 1 as a single plate spannin the relatively narrow space between t e left hand and the intermediate banks of tubes. Thus at its outer or left hand edgesaid plate is bolted to an angle iron 29 which in turn is secured to the tubes by the U-bolts of the pillow blocks. The other or right hand edge ofthe plate 15 is bent upwardly at the proper angle to fit in flat surface contact against the adjacent plate of the bafile 10, the U-bolts of the saddle blocks of the baflle 10 extending through the plate 15 with the nuts screwed up against said plate.

It is evident that with the proper looseness in the fit of the bolt holes in the late 15 its expansion or contraction Woul not exert a thrust on the tubes.

In Fig. 6, illustrating the application of my invention to a Ladd boiler, the banks of tubes 1 which connect'the mud drum 2 with the single header 3 are provided with the bafiles 30, 31 and 32 likewise comprised of plates assembled and attached to the tubes In this case the top plate of the battle 31 is shown bent over'and flanged u wardly as at 33 to be secured by the U-bo ts of the baflle 30.

In Fig. 7, illustrating the ap lication of my invention to a Parker type 0 boiler, the baffles 34, 35, 36 and 37 are horizontally disposed, as are the tubes 1, the front end of the lowermost bafile beingbolted to the front wall 38 of the fire box.

In Fig. 8, illustrating the ap lication of my invention to the Union Iron orks type of boiler wherein the banks of tubes connect the mud drum 2 with the headers 3, 4 and 5 and'the tubes 6 connect the headers 3 and 4, the baffles 39, 40, 41,42 and 42 are substantially like the bafiles 9, 10, 11 and 12 in F i 1, while the bafile. 43 is substantially like t e baflle 15 in Figs. 1 and 5. 45 represents the tube sheet.

46 represents a bafile which spans the space between two banks of tubes and also extends inside one of the banks, theintermediate bank in Fig. 8, to connect with the bafile 40. The construction of the bafile 46 is shown in detail in Figs. 9 and 10. The side of the plate is slotted as at 47 to provide clearance forthe outer row of tubes of the intermediate bank and the ends of the ton ues 48 thus formed are bent upwardly to t fiat against and to be bolted as at 49 to the baflle 40. The-bolt holes in the plate '46 are given suflicient clearance to permit the baffle 50 is s own in detail in Figs. 11

and 12, being comprised of a plurality of plates such as 50, 50, 50 and 50 disposed lengthwise between the banks of tubes with their lateral edges overlapping and bolted together as at 51. The upper end of every other plate is flanged, as at 52,'so as to be engaged by the U-bolts 22 of the saddle blocks 20 mounted on the upper bank of tubes. The lower ends of the lates are bolted to an angle bar 53 which is secured to the up er banks of tubes by the saddle blocks an U-bolts of the baffle 42.

With proper clearance in the bolt holes of the plates it is evident that they may individually expand or contract without causing the bafiie to creep, buckle or exert a thrust on the tubes.

My improved baflies are light in weight and do not distort the tubes nor cause leakage. The ease with which my bafiie may be installed and maintained enables me to position them in the boiler or still in just the proper position to obtain the best possible flow of the flaming gases.

The saddle blocks support the baflles in spaced relation to the tubes so that no portions of the tubes are masked but the entire surface areas of the tubes are exposed to. the

' full heating effect.

It is thus evident that my improved baflles are not only cheaper to install and keep in repair, but are also more eflicient than the baffles now in general use in boilers, stills and the like.

What I desire to claim is g 1. A bafiie between adjacent banks of tubes of tubular boilers, stills and the like, comprising a metal plate, saddle blocks clamped to the tubes of both banks, and means for securing the ends of the plate to said saddle blocks, said means including provision for the individual expansion and contraction of the plate independently of the saddle blocks.

2. A baflie between spaced apart banks of tubes in tubular boilers, stills and the like comprised of a plurality of relatively narrow metal plates disposed longitudinally to span the space between thebanks and having their lateral edges in sealed relation together to form a continuous bafile, and means for attaching the ends of said plates to the tubes of the two'banks.

3. A bafie between spaced apart banks of tubes in tubular boilers, stills and the like 4. A bafile between spaced apart banks of tubes in tubular boilers, stills and the like comprised of a plurality of relatively narto span the space between the banks and having their lateral edges in overlapping relation with each other to form a continuous bafiie, and means for attaching the ends of the plates to the tubes of the two banks.

5. A bafiie between spaced apart banks of tubes in tubular boilers, stills and the like comprised of a plurality of relatively narrow metal plates disposed longitudinally to span the space between the banks and having their lateral edges in overlapping relation, and means for attaching the ends of the plates to the tubes of the two banks, said plates being free to expand and contract independently of their attachment to the tubes.

6. A bafiie between spaced apart banks of tubes in-tubular boilers, stills and the like comprised of a plurality of relatively narrow inetal'plates disposed longitudinally to span the space between the banks and having their lateral edges in overla ping relation, and means for attaching t e ends of the plates to the tubes of the two banks, said plates being free to expand and contract inde endently of each other and of their attacliment to the tubes.

7. A bafile for. tubular boilers, stills and the like comprised of a plurality of metal plates assembled with sealed edges, saddle blocks spaced along the tubes and having arcuate recesses engaging the walls of the tubes and U-bolts having their loops engaging the tubes and extending through holes in the saddle blocks and in the plates to clamp the saddle blocks to the tubes and the plates to the saddle blocks. 7

8. A baflie for tubular boilers, stills an the like comprised of a plurality of metal plates assembled with sealed edges, saddle blocks spaced along the tubes and having arcuate recesses engaging the Walls of the tubes and U-bolts havmg their loops engaging the tubes and extending through holes in the saddle blocks and in the plates to clamp the saddle blocks to the tubes and the plates to the saddle blocks, said saddle blocks holding the plates in spaced relation to the tubes.

9. A bafie for tubular boilers, stills and the like comprising a plurality of relatively narrow meta plates disposed in a plane subrow metal plates disposed longitudinally stantially parallel to that of the tubes and having their lateral edge portions in contact with each other to form a continuous bafile, saddle blocks mounted on the tubes, means for anchoring the saddle blocks fixedly to the tubes and means for attaching the plates to the saddle blocks.

10. A bafile for tubular boilers, stills and the like comprising a plurality of relatively 1n thin metal plates disposed in a plane substantially parallel to that of the tubes and having their lateral edge portions in contact with each other to form a continuous baffle, saddle blocks mounted on the tubes and means for attaching the plates to the saddle blocks, said plates being free to individually expand and contract.

Signed at Pittsburgh, Pa., this 14th day of March, 1927.

CHARLES P. MILLS. 

